Positioning device

ABSTRACT

A positioning device, comprising a base element, a carrier element to be positioned relative to the base element along a z-axis as well as at least one first and one second slide element, wherein the first or second slide element on the one hand is disposed displaceably by means of a first or second base guide device along a first or second base line on the base element and on the other hand by means of a first or second ascent guide device along a first or second ascent line on the carrier element, wherein the first or second ascent line and the first or second base line run in a projection along the z-axis parallel to one another and with respectively constant different angles of inclination relative to the z-axis, and wherein the first and the second ascent guide device are arranged with respect to one another in such a manner that in at least one projection perpendicular to the z-axis, the first and the second ascent line are inclined opposite to one another relative to the z-axis. It is provided that for the synchronous displacement of the first and second slide element the positioning device comprises at least one drive device which comprises a rotary drive having an axis of rotation parallel to the z-axis and a coupling element, wherein the coupling element couples the rotary drive to the first and/or second slide element in such a manner that a rotational movement of the rotary drive causes a synchronous displacement of the first and second displacement element along the respective base lines.

REFERENCE TO RELATED APPLICATION

This application claims priority to European Patent Application No.15405038.9, filed Jun. 11, 2015. The entire disclosure of EuropeanPatent Application No. 15405038.9 is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a positioning device, which comprises a baseelement and a carrier element, which can be positioned along a z-axisrelative to the base element by displacing at least two slide elementstransversely to the z-axis.

2. Description of the Related Art

Such a positioning device is known, for example, from U.S. Pat. No.005,731,631 A. The device described there comprises a base and a carrierelement having a working surface and two parallel-running wedge surfacesopposite the working surface. The carrier element is connected to thebase by means of two spaced-apart vertical linear guides, which restrictthe movement of the carrier element relative to the base to adisplacement along the vertical z-axis. The positioning device furthercomprises as slide element two parallel-running wedges connected rigidlyto one another, which are disposed between respectively one of the wedgesurfaces of the carrier element and the base and which are connected tothe base by means of two spaced-apart linear guides. By means of the twolinear guides, the wedges can be moved along an x-axis perpendicular tothe z-axis. In addition, the upper sides of the wedges are eachconnected displaceably to the wedge surface of the carrier element bymeans of a further linear guide. A linear motor is used to move thewedges along the x-axis whereby the carrier element is moved along thez-axis relative to the base. In this case, the two vertical linearguides between the base and the carrier element prevent the carrierelement from co-moving additionally along the x-axis relative to thebase during the movement along the z-axis.

For many applications in the area of high-precision positioning however,the system stiffness of such positioning devices with vertical linearguides is frequently not sufficient. In particular, a vertical linearguide does not ensure a sufficiently high rotational stiffness about thevertical axis. In addition, a design with displacement wedges andadditional vertical linear guides is technically very complex andeconomically very expensive.

Furthermore, a positioning device with two parallel linear translationactuators is known from EP 1 911 551 A1, which are coupled to a carrierelement to be positioned via two respective parallel oriented inclinedthrust surfaces. Both thrust surfaces are inclined opposite to oneanother such that a synchronous displacement of both actuator axescauses a lifting or lowering of the carrier element. Both inclinedthrust surfaces are formed by two respectively inclined linear guiderails disposed on opposite sides of the carrier element. However, usingtwo parallel linear translation actuators is technically very complexand economically very expensive and requires a synchronization of bothdrives.

OBJECT AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to simplifytechnically the positioning devices with slide elements known from theprior.

This object is solved by a positioning device according to claim 1.Advantageous embodiments of the invention are the subject matter of thedependent claims.

The positioning device according to the preamble of claim 1—as forexample it is known from EP 1 911 551 A1—comprises a base element, acarrier element to be positioned relative to the base element along az-axis as well as at least one first and one second slide element,wherein the first or second slide element on the one hand is disposeddisplaceably by means of a first or second base guide device along afirst or second base line on the base element and on the other hand bymeans of a first or second ascent guide device along a first or secondascent line on the carrier element. In this case, the first or secondascent line and the first or second base line run in a projection alongthe z-axis parallel to one another and with respectively constantdifferent angles of inclination relative to the z-axis. The ascent linesor base lines correspond in this case to the guide paths or displacementpaths of the respective ascent or base guide devices.

Furthermore, it is provided that the first and the second ascent guidedevice are arranged with respect to one another in such a manner that inat least one projection perpendicular to the z-axis, the first and thesecond ascent lines are inclined opposite to one another relative to thez-axis.

Such an opposite arrangement of the first and second ascent guide devicehas the effect that due to a synchronous displacement of the first andthe second slide element relative to the base element along the baseguide devices, the carrier element is displaced relative to the baseelement exclusively along the z-axis and it is thereby prevented thatthe carrier element co-moves transversely to the z-axis. This isbecause, as a result of their opposite inclinations, the first and thesecond ascent guide device each mutually block a transverse movement ofthe carrier element along the first or second base guide direction orbase line. Thus, an additional vertical guide which restricts themovement of the carrier element on the z-axis can be dispensed with.Furthermore, the opposite arrangement additionally ensures a systemstiffness sufficient for already many high-precision applications.

“Synchronous displacement of the slide elements” in the sense of thisinvention means that the respective displacement movements of the firstand second slide element along the first or second base line dependingon the inclinations of the first or second ascent line with respect tothe z-axis are matched to one another in such a manner that during thesynchronous displacement along the first or second base line, the firstand the second slide element displace the carrier element along thez-axis by the same amount.

For the synchronous displacement of the first and second slide element,according to the invention, the positioning device comprises at leastone drive device, in particular a common drive device for all the slideelements, wherein the at least one drive device comprises a rotary drivehaving an axis of rotation parallel to the z-axis and a couplingelement, wherein the coupling element couples the rotary drive to thefirst, and/or second slide element in such a manner that a rotationalmovement of the rotary drive brings about a synchronous displacement ofthe first and second displacement element along the respective baselines.

For this purpose, it can be provided that the coupling element comprisesa rotating body connected rigidly to the axis of rotation and at leastone coupling member which is rotatably mounted relative to the axis ofrotation with one end on one of the slide elements and the other endradially spaced apart from the axis of rotation on the rotating body.

Any types of drives are feasible as drive device, for example, linearactuators or rotary actuators, piezo-actuators, spindle drives, linearmotors, step motors, servomotors or the like.

According to a particularly preferred embodiment of the invention, it isprovided that the coupling element couples the rotary drive to the thirdand/or fourth slide element in such a manner that a rotational movementof the rotary drive brings about a synchronous displacement of thefirst, second, third and fourth slide element along the respective baselines.

In order to increase the system stiffness, in particular the rotationalstiffness of the positioning device still further, according to anadvantageous embodiment of the invention it can be provided that thepositioning device further comprises a third and a fourth slide element.In this case, the third or fourth slide element is disposed displaceablyon the one hand by means of a third or fourth base guide device along athird or fourth base line on the base element and on the other hand bymeans of a third or fourth ascent guide device along a third or fourthascent line on the carrier element. The third or fourth ascent line andthe third or fourth base line run parallel to one another in aprojection along the z-axis and with respectively constant, differentangles of inclination relative to the z-axis. In addition, the third andfourth ascent guide device are disposed with respect to one another insuch a manner that in at least one projection perpendicular to thez-axis, the third and the fourth ascent line are inclined opposite toone another relative to the z-axis so that a synchronous displacement ofthe first, second, third and fourth slide element relative to the baseelement brings about a displacement of the carrier element relative tothe base element exclusively along the z-axis.

Instead of two or four slide elements, in principle different numbers ofsuch slide elements with a mutual blocking effect which restrict amovement of the carrier element to a displacement along the z-axis arealso feasible. Thus, for example, three, five or more slide elements canbe arranged in a polygonal configuration, distributed uniformly aboutthe z-axis. Preferably however pairs of slide elements with a mutualblocking effect are present in each case, which are arranged withrespect to one another so that in at least one projection perpendicularto the z-axis, both ascent lines of the respective part are inclinedoppositely to one another relative to the z-axis.

According to a further advantageous embodiment of the invention, thefirst and/or second base line or the first, second, third and/or fourthbase line run in a plane perpendicular to the z-axis. It can further beprovided that the first and second base line or the first, second, thirdand fourth base line are distributed uniformly about the z-axis.Alternatively or additionally, the first and second base line or thefirst, second, third and fourth base line are configuredaxis-symmetrically relative to the z-axis. It is further feasible thatthe first and second ascent line or the first, second, third and fourthascent line are configured axis-symmetrically relative to the z-axis. Asa result of these measures, in particular the technical complexity ofthe structure of the positioning device is simplified. In addition, thesynchronisation of the displacement movements of the slide element alongthe base lines is simplified.

The base guide devices or the base lines can fundamentally have anyarbitrary shape, where they are not curved along the z-axis but have aconstant angle of inclination with respect to the Z-axis greater than 0°and less than 180°. The same applies for the ascent guide devices or theascent lines, where the angle of inclination of the ascent guide devicesor ascent lines differs from the angle of inclination of therespectively corresponding base guide devices or base lines. Forexample, base guide devices which are arranged in a plane perpendicularto the z-axis and have a curved profile in the plane are feasible.Particularly preferably however the base and/or ascent guide devices areconfigured as linear guides. Thus it is provided according to anadvantageous embodiment of the invention that the first and second baseline are straight lines, in particular run parallel to one another alongan x-axis perpendicular to the z-axis. In one embodiment with a total offour slide elements, it can further be provided that the third andfourth base line are straight lines, in particular run parallel to oneanother along a y-axis perpendicular to the x and z-axis.

If the base lines are straight lines, i.e. the base guide devices areconfigured as linear guides, it is expediently the case that in such anembodiment, the respectively corresponding ascent lines are alsostraight lines or the respectively corresponding ascent guide devicesare configured as linear guides since, according to the invention, theascent lines run in a projection along the z-axis parallel to therespectively corresponding base lines.

According to a further advantageous embodiment of the invention, it isprovided that the first, second, third and/or fourth base line comprisesa ball bearing, crossed roller bearing, rolling bearing or dovetailguide. Additionally or alternatively it can be provided that the first,second, third and/or fourth ascent guide device comprises a ballbearing, crossed roller bearing, rolling bearing or dovetail guide.

In order to implement the different angles of inclination of therespectively corresponding base and ascent line, it can be providedaccording to a further advantageous embodiment of the invention that thefirst, second, third and/or fourth slide element each comprises a wedgebody on which preferably the corresponding base guide devices and ascentguide devices are arranged on opposite diverging sides of the wedge bodywhere the aperture angle of the wedge corresponds to the differenceangle between the angle of inclination of the base line and the angle ofinclination of the corresponding ascent line relative to the z-axis.

Similarly it can be provided that the carrier element comprises a first,second, third and/or fourth wedge body on which respectively the first,second, third or fourth ascent guide device is disposed. It is alsofeasible that the carrier element has a first, second, third and/orfourth sloping surface on which respectively the first, second, third orfourth ascent guide device is arranged.

The translation between the displacement movement of the slide elementalong the base line and the resulting displacement movement of thecarrier element along the z-axis can be adjusted by means of the choiceof the angle of inclination of the respective ascent line andcorresponding base line. In a particularly preferred embodiment, thefirst, second, third and fourth ascent line each enclose an anglebetween 45° and 85°, in particular between 60° and 80°, preferablybetween 71° and 79°, with respect to the z-axis.

In a further preferred embodiment of the invention, the base elementcomprises a plate, in particular a frame-like plate with a throughopening. Similarly, it can be provided that the carrier elementcomprises a frame, in particular a rectangular, preferably square frame.This design results in a particularly rigid positioning device with ahigh system stiffness.

In the sense of a very compact design of the positioning device, it canfurther be provided that the first and the second ascent guide deviceare disposed on opposite sides of the carrier element and/or that thethird and the fourth ascent guide device are disposed on opposite sidesof the carrier element.

Further objects, aims, advantages and possible applications of thepresent invention are obtained from the following description of anexemplary embodiment of the invention depicted in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the figures:

FIG. 1 shows a perspective view of a possible exemplary embodiment of apositioning device according to the invention;

FIG. 2 shows an exploded view of the positioning device according toFIG. 1;

FIG. 3 shows a plan view of the positioning device according to FIG. 1;

FIG. 4 shows a cross-section through the positioning device according toFIG. 1 along the z-axis; and

FIG. 5 shows a side view of the positioning device according to FIG. 1along the y-axis.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

FIGS. 1 to 5 show a possible exemplary embodiment of a positioningdevice 1 according to the invention. The positioning device 1 comprisesa flat base element 2 configured as a frame-like plate 4 with throughopening as well as a carrier element 3 to be positioned relative to thebase element 2 along a z-axis, which is also configured in the form of asquare frame 5.

For displacement of the carrier element 3 along the z-axis, thepositioning device 1 further comprises a first, a second, a third and afourth slide element 11, 12, 13, 14. The four slide elements 11, 12, 13,14 are in this case arranged displaceably in a common planeperpendicular to the z-axis and in a rectangular configurationdistributed uniformly about the z-axis between the carrier element 3 andthe base element 2.

Respectively a first, second, third or fourth base guide device 21, 22,23, 24 and a first, second, third or fourth ascent guide device 31, 3233, 34 are disposed on the first, second, third and fourth slide element11, 12, 13, 14.

By means of the first or second base guide device 21, 22, the first orsecond slide element 11, 12 is displaceable relative to the base element2 along a first or second base line 121, 122 which runs along an x-axisaligned perpendicular to the z-axis. Accordingly, the third or fourthslide element 13, 14 is disposed linearly displaceably on the baseelement 2 along a third or fourth base line 123, 124 which runs along ay-axis aligned perpendicularly to the x and y-axis by means of a thirdor fourth base guide device 23, 24.

The respective base guide devices 21, 22, 23, 24 are each disposed on abase side of the slide elements 11, 12, 13, 14 configured as wedgebodies. The respective ascent guide devices 31, 32, 33, 34 are disposedon the sloping side of the wedge-like slide elements 11, 12, 13, 14opposite the respective base side, by means of which the slide elements11, 12, 13, 14 are connected linearly displaceably to correspondingsloping surfaces of the carrier element 3 along a first, second, thirdor fourth ascent line 131, 132, 133, 134.

The sloping sides on the carrier element 3 on which respectively thefirst, second, third, or fourth ascent guide devices 31, 32, 33, 34 aredisposed are each formed by a first, second, third or fourth wedge body41, 42, 43, 44. These wedge bodies 41, 42, 43, 44 are arrangedcorresponding to the wedge-like slide elements 11, 12, 13, 14 in arectangular configuration distributed uniformly about the z-axis on theouter sides of the frame-like carrier element 3. For better connectionof the wedge bodies to the frame 5 of the carrier element 3, the fourwall elements from which the frame 5 is constructed each project at onecorner of the frame so that the wedge bodies 41, 42, 43, 44 each abutagainst two wall surfaces of the frame 5 arranged at right angles to oneanother. By this means the system stiffness of the positioning device 1is sometimes additionally increased.

As can be seen in particular in FIGS. 3 and 5, the ascent lines 131,132, 133, 134 and the corresponding base lines 121, 122, 123, 124 areeach arranged parallel, in particular congruently above one another ineach case, in a projection along the z-axis. Each of the four ascentlines and each of the corresponding four base lines has a constant angleof inclination with respect to the z-axis, where the angle ofinclination of the respectively corresponding ascent and base linesdiffer. In the present exemplary embodiment, the angle of inclination ofthe base lines relative to the z-axis is 90°. In comparison, the ascentlines or the sloping surfaces of each of the wedge-shaped slide elements11, 12, 13, 14 enclose an angle of inclination a of about 76° withrespect to the z-axis. Preferably the angle of inclination a should liein the range between 71° and 79°.

In a projection along the y-axis, the sloping surfaces of thewedge-shaped first and second slide elements 11, 12 and accordingly thefirst and second ascent guide devices 31, 32 are oriented oppositelyinclined with respect to one another in the manner according to theinvention. Similarly, in a projection along the x-axis, the slopingsurfaces of the wedge-shaped third and fourth slide elements 13, 14 andaccordingly the third and fourth ascent guide devices 33, 34 areoriented oppositely inclined with respect to one another according tothe invention. As a result, due to the opposite inclined arrangement ofthe slide elements and the ascent guide devices, it is achieved that asynchronous displacement of the first and the second slide element 11,12 in opposite directions along the x-axis and of the third and fourthslide elements 13, 14 in opposite directions along the y-axis bringsabout a displacement of the carrier element 3 exclusively along thez-axis. This is because, as a result of their opposite inclination, thefirst and the second ascent guide device 31, 32 or the third and fourthascent guide device 33, 34 each mutually block a transverse movement ofthe carrier element along the x or y-axis. An additional linear guidealong the z-axis which would restrict the movement of the carrierelement to the z-axis can therefore be dispensed with.

In the present exemplary embodiment, all the base guide devices 21, 22,23, 24 and ascent guide devices 31, 32, 33, 34 are configured as linearguides with roller bearings. Naturally, other types and designs oflinear guides are also feasible.

For the synchronous displacement of the four slide elements 11, 12, 13,14, the positioning device 1 according to the present exemplaryembodiment has a common drive device for all four slide elements 11, 12,13, 14. The common drive device comprises a rotary drive 9 with an axisof rotation parallel to the z-axis and a coupling element 6, where thecoupling element couples the rotary drive to the first, second, thirdand fourth slide element 11, 12, 13, 14 in such a manner that arotational movement of the rotary drive 9 brings about a synchronousdisplacement of the first, second, third and fourth slide element 11,12, 13, 14 along the respective base lines, i.e. along the x or y-axis.For this purpose, the coupling element 6 comprises a rotational body 7connected rigidly to the axis of rotation and a total of four couplingmembers 8 which are rotatably mounted with respect to the axis ofrotation with one end on each one of the slide elements 11, 12, 13, 14and the other end radially spaced from the axis of rotation on therotational body 7.

As a result of the same angle of inclination of the four ascent guidedevices 31, 32, 33, 34 relative to the z-axis, the rotation of the drivedevice about the z-axis brings about a synchronous displacement of allfour slide elements 11, 12, 13, 14 which in turn raise the carrierelement 3 uniformly along the z-axis. The rectangular or squarearrangement of the four slide elements is characterized in particular bya sufficiently high system stiffness for high-precision applications.

The present invention has been described in the context of one or moreembodiments, and variations and examples thereof. It is to beunderstood, however, that other expedients known to those skilled in theart or disclosed herein may be employed without departing from thespirit of the invention.

Therefore, it is intended that the appended claims be interpreted asincluding the embodiment(s) described herein, any alternatives mentionedabove, and all equivalents thereto.

What is claimed is:
 1. A positioning device, comprising a base element,a carrier element to be positioned relative to the base element along az-axis as well as at least one first and one second slide element,wherein the first or second slide element on the one hand is disposeddisplaceably by means of a first or second base guide device along afirst or second base line on the base element and on the other hand bymeans of a first or second ascent guide device along a first or secondascent line on the carrier element, wherein the first or second ascentline and the first or second base line run in a projection along thez-axis parallel to one another and with respectively constant differentangles of inclination relative to the z-axis, wherein the first and thesecond ascent guide device are arranged with respect to one another insuch a manner that in at least one projection perpendicular to thez-axis, the first and the second ascent line are inclined opposite toone another relative to the z-axis so that a synchronous displacement ofthe first and the second slide element relative to the base elementcauses a displacement of the carrier element relative to the baseelement exclusively along the z-axis, characterized in that for thesynchronous displacement of the first and second slide element thepositioning device comprises at least one drive device which comprises arotary drive having an axis of rotation parallel to the z-axis and acoupling element, wherein the coupling element couples the rotary driveto the first and/or second slide element in such a manner that arotational movement of the rotary drive causes a synchronousdisplacement of the first and second displacement element along therespective base lines.
 2. The positioning device according to claim 1,which further comprises a third and a fourth slide element, wherein thethird or fourth slide element is disposed displaceably on the one handby means of a third or fourth base guide device along a third or fourthbase line on the base element and on the other hand by means of a thirdor fourth ascent guide device along a third or fourth ascent line on thecarrier element, wherein the third or fourth ascent line and the thirdor fourth base line run parallel to one another in a projection alongthe z-axis and with respectively constant, different angles ofinclination relative to the z-axis, and wherein the third and fourthascent guide devices are disposed with respect to one another in such amanner that in at least one projection perpendicular to the z-axis, thethird and the fourth ascent line are inclined opposite to one anotherrelative to the z-axis so that a synchronous displacement of the first,second, third and fourth slide element relative to the base elementcauses a displacement of the carrier element relative to the baseelement exclusively along the z-axis.
 3. The positioning deviceaccording to claim 1, characterized in that the first and/or second baseline or the first, second, third and/or fourth base line run in a planeperpendicular to the z-axis.
 4. The positioning device according toclaim 1, characterized in that a. the first and second base line or thefirst, second, third and fourth base line are distributed uniformlyabout the z-axis; b. the first and second base line or the first,second, third and fourth base line are configured axis-symmetricallyrelative to the z-axis; and/or c. the first and second ascent line orthe first, second, third and fourth ascent line are configuredaxis-symmetrically relative to the z-axis.
 5. The positioning deviceaccording to claim 1, characterized in that the first and second baselines are straight lines, in particular run parallel to one anotheralong an x-axis perpendicular to the z-axis, preferably that the thirdand fourth base lines are straight lines, in particular run parallel toone another along a y-axis perpendicular to the x- and z-axis.
 6. Thepositioning device according to claim 1, characterized in that a. thefirst, second, third and/or fourth base line comprises a ball bearing,crossed roller bearing, rolling bearing or dovetail guide; and/or b. thefirst, second, third and/or fourth ascent guide device comprises a ballbearing, crossed roller bearing, rolling bearing or dovetail guide. 7.The positioning device according to claim 1, characterized in that thefirst, second, third and/or fourth slide element each comprises a wedgebody.
 8. The positioning device according to claim 1, characterized inthat the carrier element comprises a first, second, third and/or fourthwedge body on which respectively the first, second, third or fourthascent guide device is disposed.
 9. The positioning device according toclaim 1, characterized in that the first, second, third and fourthascent line each enclose an angle (a) between 45° and 85°, in particularbetween 60° and 80°, preferably between 71° and 79°, with respect to thez-axis.
 10. The positioning device according to claim 1, characterizedin that the base element comprises a plate, in particular a frame-likeplate with a through opening.
 11. The positioning device according toclaim 1, characterized in that the carrier element comprises a frame, inparticular a rectangular, preferably square frame.
 12. The positioningdevice according to claim 1, characterized in that the first and thesecond ascent guide device are disposed on opposite sides of the carrierelement and/or that the third and the fourth ascent guide device aredisposed on opposite sides of the carrier element.
 13. The positioningdevice according to claim 2 characterized in that the coupling elementcouples the rotary drive to the third and/or fourth slide element insuch a manner that a rotational movement of the rotary drive causes asynchronous displacement of the first and second displacement element orof the first, second, third and fourth slide element along therespective base lines.
 14. The positioning device according to claim 1,characterized in that the coupling element comprises a rotating bodyconnected rigidly to the axis of rotation and at least one couplingmember which is rotatably mounted relative to the axis of rotation withone end on one of the slide elements and the other end radially spacedapart from the axis of rotation on the rotating body.